Method and apparatus fob water



May 20, 1941' C. R'. WGNER ETAL Re. 21,809

METHOD ANDAPPARATUS FOR WATER-DRIVE PRODUCTION OF MINERAL OIL Original Filed July 6, 1957 INVENTOR Cary R Wagner' BY Richard I7'. fart" 5M IV* ATTORNEY can be forced into the well, or making Ressued May 20, 1941 UNITED STATES PATENT O Re. 21,809 FICE METHOD AND APPARATUS FOR.. WATER- DRIVE PRODUCTION OF MINERAL OIL Cary R. Wagner and Richard H. Carr,

Chicago,

Ill., assignors to The Pure Oil Company, Chicago, Ill., a corporation'of Ohio Original No. 2,152,779, dated April 4, 1939, Serial No. 152,087, July 6, 1937. Application for reissue April ZZ, 1940, Serial No. 331,061

(Cl. 16S-21) 14 Claims.

This invention relates to method and apparatus for Walter-drive production of mineral oil and is more particularly concerned with the problem of flooding of oil wells or the use of wavter drive in connection therewith.

It has become common practice in the art of producing petroleum to V`use water drive to increase the amount and rate of production. The water is forced under pressure into the injection well and penetrates the producing formation in the direction of the surrounding wells, thereby driving th'e oil toward the wells.

The water for the flooding is generally obtained by drilling one or more Water wells in the vicinity of the producing wells and by pumping water from these wells to the producing wells. This water invariably contains a small percentage of iron inthe form of soluble'ferrous compounds,

usually ferrous hydroxide. The iron content may vary from 0.5 part of iron per million parts of water Ito 5 `or more parts of iron lper million, depending upon the formation from which the water is obtained It is known that this iron is precipitated when l pumped into the injection well and deposits on the walls'of fthe well in the form of a gel. thereby either greatly reducing the quantity of water that it totally impossible to inject additional water.

In order to avoid the precipitation of iron with its attendant consequences, it has been common practice to aerate the water by blowing air therethrough in tanks whereby iron is precipitated and then to filter the aerated water through beds of sand of various degrees of fineness to remove the precipitated iron and other solid material from the'water. It has been considered necessary to reduce -the iron content of the water below .5 part per million in order to get satisfactory results. However, it has been found kthat although the treatment of water in the manner just described, delays the clogging, of the injecting well, it does not entirely avoid it.

tities in which it is present. But upon oxidation rto the ferric state, compounds, such as ferrie hydroxide, are formed which are insoluble in the proportion in which they are present. These ferric compounds cause rthe clogging of the well.

Even when the water is aerated and filtered it apparentlyv retains or picks up additional iron, which precipitates in the well. Eiorts to remove occluded air from the Water after aeration and filtration by means of vacuum have not remedied the difficulty. The iron which is picked up is probably due to corrosion of the pipe line p and to solution of ferrous iron in the washer.

In carrying out the invention, water is pumped from the water well to the injection well under a blanket of natural gas which is obtained from storage or directly from wells in the vicinity. A small gas pressure is kept above the water in the water wells as well as above the water in the injection wells.l i In this manner, access of air to the water is prevented and *the water, therefore, passes unchanged from one well to the other.

The accompanying drawing, the single gure of which is a diagrammatic side elevational View, illustrates apparatus suitable for carrying out the invention.

Referring to the drawing, the numeral I represents a water well closed at the top by means of closure mem-ber 3 in order to prevent access of air into the well. Tubing 5 extends through the closure to the bottom of the well. A polish rod 1, located inside the tubing 5, has a pump 9 fastened to the lower end thereof. The polish rod is adapted to be reciprocated up and down in the tubing 5 and is properly packed at the point where it passes through Ithe upper end of the tubing in order to prevent-leakage of air into the tubing.

It has been discovered that Ithe difficulties hereinbefore attendant upon the use of water drive are completely overcome if the well water is injected into the injection well without any treatment and' air is entirely excluded from contact with the water. It has further been discovered that the iron present in solution in the Well water will remainin solution after injection into the injection well provided the well is blanketed v with an inert gas such as carbon dioxide, nitrogen, orV natural gas. Precipitation does not take place under such conditions and the well remains entirely free from clogging thereby permitting injection of large quantities of water and increasing the production of oil in the surrounding wells.

As long as the iron is maintained in the ferrous state it is soluble in the water in the quan- The upper end of tubing 5 is connected by means of conduit I I to an air tight sand filter I3 which may preferably `be made up of successive layersv of sand, each of finer mesh than the next lower layer. In passing through the sand bed, any suspended material present in the water is removed. It is desirable to remove suspended matter since it clogs up the minute pores in the producing formation. The filtered water leaves the top of the sand lter through conduit I5 and passes to closed ,storage tank I1. 4'I'he top of the tank is provided with a safety pop valve I9 to relieve excess pressure in the tank. The tank is also provided with a U-tube 2|, sealed with oil,

in order to determine the level of the water in the tank.

- A conduit 23 .connects the lower portion of tank I1 with a pump 25 which in turn is connected -by conduit 21 to the top of an injection well 29. 'I'he top of the well 29 is closed by closure or cap 3I to prevent air from entering the well.

The'line 33 is connected to any suitable source of inert gas, as for example, a tank of natural gas. A pressure regulator 35 permits the gas to iiow from the gas source at a xed pressure. In this particular case, a pressure of V4 pound above atmospheric has been found satisfactory. From the line 33 the gas enters manifold 31 from which it is distributed to line 39 entering Thus, in accordance with this invention, water' amounts of soluble containing relatively large iron compounds can be injected directly into earth bores without running any risk of clogging the bore hole. This discovery not only eliminates the use of expensive treating methods but actually enables the production of larger amounts of oil because of the large amounts of water than can be forced through the producing strata.

What is claimed is:

1. -In the transfer of water into an earth bore, the method of preventing clogging of said earth bore into which is injected said water containing solublecompounds which precipitate upon oxidation which comprises maintaining the water at its sourceunder a blanket of inert gas, transferring the water from its source to the injection bore in the absence of ai: or oxygen, and injecting the water, without treatment to remove said compounds therefrom, into the injection bore under a blanket of inert gas.l 2. 'I'he method ,of flooding oil-bearing formations which comprises withdrawing water from a well maintained under a blanket of inert gas, transferring the water through a closed conduit to a closed container in which the water is maintained under an atmosphere of inert gas, transferring water from said container through a closed conduit to a water injection well maintained under a blanket of inert gas, all without removing from said water any soluble iron compounds.

3. Method in accordance with claim 2 in which the water is ltered in the absence of air prior to injection into the injection well.

4. Apparatus for transferring subsurface water from one' deep well to another which comprises a pump located in one of said wells, the top of said well being closed oil from the atmosphere,

a closed conduit from .said wellto a closed tank.y

a second conduit from said tank to the other of said wells, a closure on the top of said well to prevent access of air, a gas holder, conduits from said gas holder to the tops of said well and to said tank, and automatic means for releasing pressure in said tank.

5. Apparatus in accordance with claim 4 including a filter in the conduit from the first mentioned well to said tank. g

6; In the flooding of oil-bearing 'formations with water containing appreciable quantities ofl compounds which precipitate upon oxidationfthe steps of maintaining the water at its source under a blanket of inert gas, transferring the water from its source to the injection bore in the absence of air or oxygen,

without treatment to remove oxidized precipitated compounds therefrom, into the injection bore under a blanket of inert gas. I

7. In the transfer of water containing appreciablequantities of iron compounds in solution into an earth bore, the method of preventing clogging of said said Awater which comprises maintaining said water under a blanket of inert gas and transferring said water from its source to the earth bore, in the absence of air or oxygen, without subjecting. it to treatment to remove iron or its compounds.

8. In the flooding of oil-bearing formations with water containing appreciable quantities of iron compounds in solution the steps of maintaining the source of water under a blanket of inert gas, transferring the water from the source to an injection well through a closed conduit in the substantialv absence of air or oxygen and injecting the water into the injection well under a blanket of inert gas without removing from the water any of its iron content.

9. Method in accordance with claim 1 in which l the water is filtered in the absence of air prior to injection into the injection bore.

v 10. Method in accordance with claim 1 where.

the blanket of inert gas is composed of hydrocarbon gases. V

11. Method in accordance with claim 1 where the blanket of inert gas is composed of carbon dioxide.

12. In the transfer of water into an earth bore the method of preventing clogging of said earth bore into which is injected said water containing soluble compounds which precipitate upon oxidation which comprises maintaining the water at its source under an inert fluid capable of forming a protective blanket over the surface of the water, transferring the water from its source to the injection bore in the absence of air or oxygen and injecting the water without treatment to remove said compounds therefrom into the injection bore under a blanket of inert fluid.

and injecting the water 13. In the flooding of oil .bearing formations with water containing appreciable quantities of compounds which precipitate upon oxidation, the steps of maintaining the source of water under a closed system in the absence of air or oxygen, transferring the water from the source through a closed conduit to a storage vessel in which air or oxygen is excluded fromsaid water by an inert fluid capable of forming a protective blanket over thev surface of the water, transferring the water from said storage vessel to an injection well through a closed conduit and injecting .the water into the injection well in a closed system in the absence of air or Voxygen and without removing from the water any of said compounds.

14. In the transfer of water containing appreciable quantities of iron compounds in solution into an earth bore, the methodvof preventing clogging of said earth bore into which is injected said water which comprises maintaining said water under an inert uid capable of forming a protective blanket over --the surface of the Water and transferring said water from its source to the earth bore in the absence of air or oxygen without subjecting it to treatment to remove iron or its compounds.

CARY R.. WAGNER.

RICHARD H. CARR.

earth bore into which is injected 

